Long-term changes in population genetic features of a rapidly expanding marine invader: implication for invasion success

Large blooms of Rhopilema nomadica, a highly venomous rhizostamatid scyphozoan species introduced to the Mediterranean through the Suez Canal, have become ubiquitous in the summer and winter months along the Israeli coasts since the mid-1980s. This species has since spread across the eastern Mediterranean and was sighted as far west as Tunisia and Sardinia. For the past 12 years, we have studied changes in the mitochondrial COI haplotypes diversity of R. nomadica to investigate small scale fluctuactions of genetic diversity and to reveal possible genetic structuring of the fast spreading invader in the Eastern Mediterranean. The 1091 COI sequences analysed, revealed a highly diverse population displaying 89 haplotypes, 46 of which appeared as singletons, low frequency haplotypes. All the specimens analysed throughout the period belong to a single unstructured population. Though lacking data from the source population in the Red Sea, the high within-population diversity and the high diversity of COI haplotypes support the hypothesis of multiple introductions events, or an open corridor with a continuous influx of propagules. Tajima’s D and Fu’s Fst negative values and the increased numbers of COI singletons from early to late sampling periods, have verified that the Israeli population is characterized by a rapid expanding population. Further research is needed for the evaluation of COI diversity and patterns in R. nomadica populations across the eastern Mediterranean Sea and Red Sea, as well as any correlation of the high variability between COI locus and phenotypic diversity.

     

Myeloid Derived Suppressor Cells (MDSCs) Are Increased and Exert Immunosuppressive Activity Together with Polymorphonuclear Leukocytes (PMNs) in Chronic Myeloid Leukemia Patients

Tumor immune tolerance can derive from the recruitment of suppressor cell population, including myeloid derived suppressor cells (MDSCs), able to inhibit T cells activity. We identified a significantly expanded MDSCs population in chronic myeloid leukemia (CML) patients at diagnosis that decreased to normal levels after imatinib therapy. In addition, expression of arginase 1 (Arg1) that depletes microenvironment of arginine, an essential aminoacid for T cell function, resulted in an increase in patients at diagnosis. Purified CML CD11b+CD33+CD14-HLADR- cells markedly suppressed normal donor T cell proliferation in vitro. Comparing CML Gr-MDSCs to autologous polymorphonuclear leukocytes (PMNs) we observed a higher Arg1 expression and activity in PMNs, together with an inhibitory effect on T cells in vitro. Our data indicate that CML cells create an immuno-tolerant environment associated to MDSCs expansion with immunosuppressive capacity mediated by Arg1. In addition, we demonstrated for the first time also an immunosuppressive activity of CML PMNs, suggesting a strong potential immune escape mechanism created by CML cells, which control the anti-tumor reactive T cells. MDSCs should be monitored in imatinib discontinuation trials to understand their importance in relapsing patients.     

Grafted Neural Precursors Integrate Into Mouse Striatum,Differentiate and Promote Recovery of Function Through Release of Erythropoietin in MPTP-Treated Mice

Erythropoietin-releasing neural precursor cells (Er-NPCs) are a subclass of subventricular zone-derived neural progenitors, capable of surviving for 6 hr after death of donor. They present higher neural differentiation. Here, Er-NPCs were studied in animal model of Parkinson’s disease. Dopaminergic degeneration was caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine intraperitoneal administration in C57BL/6 mice. The loss of function was evaluated by specific behavioral tests. Er-NPCs (2.5 × 10⁵) expressing the green fluorescent protein were administered by stereotaxic injection unilaterally in the left striatum. At the end of observational research period (2 weeks), most of the transplanted Er-NPCs were located in the striatum, while several had migrated ventrally and caudally from the injection site, up to ipsilateral and contralateral substantia nigra. Most of transplanted cells had differentiated into dopaminergic, cholinergic, or GABAergic neurons. Er-NPCs administration also promoted a rapid functional improvement that was already evident at the third day after cells administration. This was accompanied by enhanced survival of nigral neurons. These effects were likely promoted by Er-NPCs-released erythropoietin (EPO), since the injection of Er-NPCs in association with anti-EPO or anti-EPOR antibodies had completely neutralized the recovery of function. In addition, intrastriatal administration of recombinant EPO mimics the effects of Er-NPCs. We suggest that Er-NPCs, and cells with similar properties, may represent good candidates for cellular therapy in neurodegenerative disorders of this kind.     

Developmental changes of neuron-specific enolase mRNA in primary cultures of rat neurons

1. The level of mRNAs for neuron-specific enolase (NSE) and nonneuronal enolase (NNE) was studied in developing rat brain and in pure neuronal cultures of corresponding ages treated or not treated with triiodothyronine (T3). 2. In brain cortices both messages are already detectable at the earliest age (embryonal day 16; E16). During development the mRNA for NNE remains at a steady level, with a transient decline at postnatal day 5 (P5). 3. On the other hand, NSE mRNA follows a biphasic curve: the signal increases threefold from E-16 to P0 and threefold from P5 to P18, with a plateau between P0 and P5. 4. In neuronal cultures the NNE message is present at a constant level until day 10 and declines sharply thereafter, while in T3-treated cultures it reaches a minimum beforehand. 5. The NSE mRNA, on the other hand, increases continuously throughout the whole culture life span, and a slightly higher level is observed in T3-treated cells during the first ten days.     

The Use of an Automated System (GreenFeed) to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Ruminant animals (domesticated or wild) emit methane (CH₄) through enteric fermentation in their digestive tract and from decomposition of manure during storage. These processes are the major sources of greenhouse gas (GHG) emissions from animal production systems. Techniques for measuring enteric CH₄ vary from direct measurements (respiration chambers, which are highly accurate, but with limited applicability) to various indirect methods (sniffers, laser technology, which are practical, but with variable accuracy). The sulfur hexafluoride (SF₆) tracer gas method is commonly used to measure enteric CH₄ production by animal scientists and more recently, application of an Automated Head-Chamber System (AHCS) (GreenFeed, C-Lock, Inc., Rapid City, SD), which is the focus of this experiment, has been growing. AHCS is an automated system to monitor CH₄ and carbon dioxide (CO₂) mass fluxes from the breath of ruminant animals. In a typical AHCS operation, small quantities of baiting feed are dispensed to individual animals to lure them to AHCS multiple times daily. As the animal visits AHCS, a fan system pulls air past the animal’s muzzle into an intake manifold, and through an air collection pipe where continuous airflow rates are measured. A sub-sample of air is pumped out of the pipe into non-dispersive infra-red sensors for continuous measurement of CH₄ and CO₂ concentrations. Field comparisons of AHCS to respiration chambers or SF₆ have demonstrated that AHCS produces repeatable and accurate CH₄ emission results, provided that animal visits to AHCS are sufficient so emission estimates are representative of the diurnal rhythm of rumen gas production. Here, we demonstrate the use of AHCS to measure CO₂ and CH₄ fluxes from dairy cows given a control diet or a diet supplemented with technical-grade cashew nut shell liquid.